MADILL 122 INTERLOCK SWING

Rob Prebble

ABSTRACT A Madill 122 was studied operating with a scab skyline system clea~elling45 year old Douglas Fir in Oregon, USA. The trees had been cut into log length at the stump and average extracted piece size was .71m3. From the data, estimated productivity was around 290m3for an eight hour shiJt but this particular crew actually worked nine hours and productivity was closer to 325m3. Work- in that extra hour reduced the unit cost per m5 by 7%. Machine utilisation was high at 82% and one of the contributing factors was the use of a mobile tailhold which kept lineshifi times to a minimum. Extended hours of operation with regular cycles and consistent drag volumes will be es- sential for a machine like the Madill 122 to be successful in New Zealand. Loggers may be forced to mechanise felling and delimbing to attain the increased productivity necessay.

If mechanical slack pulling (MSP) operation Figure 1 :Madill 122 with scab skyline system is anticipated over long haul distances (375m or greater), the Madill 123 swing yarder would be a better machine. INTRODUCTION ACKNOWLEDGEMENTS Swing are popular Elders Resources NZFP for awarding a machines in the Pacific Northwest. They Jubilee Scholarship to fund the travel, con- are predominantly used as grapple yarders tractor Whitaker and crew for their coopera- in Washington and British Columbia espe- tion during the study and forest owner cially in the younger second growth clear- Weyerhaeuser Co. felling operations (Peterson, 1987, Peter- son, 1988). Loggers in Oregon and further designed primarily for grapple yarding but south tend to use swing yarders more with quite capable of MSP carriage logging. It carriage and choker systems in old growth has interlock in both directions and having as well as second growth stands. Some of interlock on the outhaul improves control the larger contractors use their swing yar- of the unloaded grapple during outhaul. ders to log areas where access is too dif- The 122 has a proven record of efficiency ficult, or hauling distances too short and and reliability in British Columbia uneconomic for their 27m tower machines. (MacDonald, 1987) and two are now work- ing in Tasmania. Most swing yarders manufactured these days have an interlock mechanism between The potential for swing yarders in New the tailrope drum and the mainrope drums. Zealand is in areas where the terrain is Interlock allows energy, normally lost to relatively easy but soil instability is going to heat generated by the braking required to restrict road and landing construction to a restrain the outwinding drum, to be minimum e.g. Mangatu and Ruatoria regenerated to the shaft or shafts driving Forests on the East Coast. To effectively the inwinding drum(s), through a slipping plan for these machines, logging managers clutch or planetary gear system. The de- need good base information to work from. gree of interlocking must be infinitely ad- Knowledge of machine cycle times, justable to account for variations in rope payload capacity and the type of terrain tensions and the changing diameter of the and systems they are best suited to are es- drums. Some machines have interlock sential ingredients. operating in both directions i.e. outhaul and inhaul, while others just have inter- A Madill 122 swing yarder working on locking on the inhaul. Weyerhaeuser's land, near Springfield, Oregon was production studied in Decem- The geometry of the "A" frame guyline ber 1988. This report summarises the data fairlead on swing yarders enables the collected. machine to pivot around the centre point of the turntable without adjusting guyline length. This allows drags to be dropped alongside the machine which reduces land- ing requirements and makes the logs more THE MACHINE accessible for the next phase of the opera- tion. Generally swing yarders are mounted The Madill 122 is a track mounted swing on hydrastatically driven track undercar- yarder manufactured by S. Madill Limited riages which gives them good traction and in their Nanaimo plant on Vancouver Is- gradeability to negotiate difficult access land. Basic specifications are: tracks.

One of the most popular swing yarders in Engine - 317 kw G.M. 8V92TA the Canadian industry has been the Madill or 298 kw Cummins 044, a 95 tonne grapple yarding crane with NTA855C a 335 kW V-12m engine. These machines Converter - Twin Disc type 4 are designed for high speed logging over Transmission - Twin Disc 2800 short distances and while they have a his- series Ratio 2:l tory of good performance, they are very Undercarriage - 087 hydraulically heavy machines, have a high capital cost driven track mount and are relatively expensive to run. (The capable of speeds of 044 does not have interlock which means 4 kph that it relies on a powerful V-12 engine and Swing speed - 0 - 3.5 rpm water cooled brakes on the tailrope drum to maintain tension in the lines). Gradeability - 36% unassisted

With the development of interlock, Tower - live boom lattice manufacturers are moving towards lighter, steel construction faster machines with more flexibility. The Working height to top of tailrope Madill 122 is one of these new machines f airlead - 16m Drum Ca~acitiesand Performance

Drum Rope Size Operating Mid drum Mid drum (m) Capacity Line pull* Line speed** (m) (kg) (m/m)

Mainrope.

Slackpull er

Tailrope 22 884 11186 819

Strawline 10 1341 3463 1364

Guylines (2) 2 6 60 6520 34

*At stall on the torque converter **In a no load situation.

The 122 also has a topping drum which is used to raise and lower the main boom.

Clutches and Brakes

Drum Clutch Interlock Brakes

Mainrope B .F, Goodrich 26x5 Wichita 124, Water cooled 30" x 4 " Band

Slackpuller B.F. Goodrich 26x5 Wichita 124, Water cooled 30" x 4" Band

Tailrope B.F. Goodrich 26x5 Wichita 224, Water cooled 30" x 4" Band

Strawline Wichita 21 6 - 3211x2.5" Band

Operating weight - 52,300 kg Length - 5.5m carrier only, with tower lowered, 18.9m overall Price as at December 1988 - US$575,000

LOGGING SYSTEM Average extracted piece size was .71m3. The Madill 122 was working in 45 year old For most of the study there were three Douglas fir clearfell. It was rigged as a breaker-outs and a tender (crewboss) scab skyline with four 7m long strops on hooking logs on (see Figure 2). Towards the butt rigging. The trees had been cut the end of each line the hook tender would into log length at the stump by contract leave the breakout site to prepare for the fallers. Four log segregations had been cut lineshift. A cat D7 with a blade mounted with two main sorts and two minor sorts. "A" frame was used as a mobile tailhold. The landing was located on a widened STUDY METHOD curve in the road. Logs were being pulled uphill to the road edge and swung to within reach of the loader. The loader was a A total of 70 cycles were recorded on a track mounted 38 tonne Barko 475 with a continuous time study basis. A ground live heel and an llm boom reach. One profile was run to get indicative hauling chaser (unhooker) was on the landing and distances and this is shown in Figure 3. occasionally the side-rod (a supervisor Scaled log volumes from the truck loadout employed by the contractor) assisted with were used to derive an average piece size the unhooking and delimbing. for the study. The loader and chaser were activity sampled concurrently with the hauler cycles and these have been reported separately (Prebble, 1989).

SWING YARDER MOBILE TAILHOLC

Figure 3 :Ground profile for 122 Madill study

RESULTS

Average cycle times from the study data are shown in Table 1. Four breaker-outs were hooking on for over 75% of the Figure 2 :There was usually 1 man per strop hooking cycles. logs on in the 122 operation. Using a scab skyline system, the Madill 122 was producing around 38m3 per available machine hour which is high compared to a Since purchasing the 122 in 1987, contrac- similar study of a Washington 88 log length tor Don Whitaker has found that the operation in New Zealand (Prebble, 1988). machine is under-utilised pulling log length While the 88's cycle times were slightly logs in small timber. During 1988 the sys- faster, average piece size was only .50 and tem was changed to a tree length operation the resultant smaller drag size meant with a stroke boom delimber at the land- productivity was much lower than the 122. ing. While this improved the productivity of the hauler (Pease, 1988) the delimber The outhaul speeds of 312m/min in the 122 was then under-utilised. To overcome this, study were considerably slower than a grapple was put on the rigging in 1989 specification and more inconsistent than and a added to bunch trees would be e ected from a machine of this for the grapple. This change has balanced capability (? value of only .49). Frequent the system but the capital cost of the equip- wrapping of the unloaded tailrope caused ment alone is somewhere in the region of by a single block at the tailhold, meant that NZ$2,300,000. Neither the delimber or the the operator had to outhaul slowly until the feller buncher were in operation during the rope unwrapped. The problem was not study that this report is based on. evident during inhaul. Table 1 :Average cycle times for tached per drag. There was no significant Madill 122 difference in hauler productivity between three and four breaker-outs. Three lineshifts were observed during the Element Time, mins study and these averaged less than five minutes per shift. The D7 mobile tailhold helped keep rigging time per cycle low. Sample size 70 One 10 minute re-positioning of the swing yarder was recorded and this involved Raise rigging .25 moving the machine along the road Outhaul .64 (200m) (approximately 5m) and changing guyline position(') .66 locations. Hook on 1.87 (5.77 pcs) Breakout .25 Assuming an availability of 95% for a Inhaul .92 swing yarder (derived from Prebble 1988, Lower rigging .22 MacDonald 1987) productivity would have Unhook .77 been around 290m3 per eight hour shift. The particular crew studied normally worked a nine hour shift and their produc- Delay free total 5.58 (SD = 1.35) tivity would have been closer to 325m3. Machine utilisation was very high at 82%. Production delays .09 Landing delays .08 Rigging .37 Other -39 COSTS

Total cycle time 6.51 Based on LIRA'S costing format (Wells, Pieces/cycle 5.77 1981) a logger would need around $4200 Ave piece size .71 per day for a new Madill 122, a 30 tonne Ave drag size 4.09 loader and ten men (see Table 2). At 290m3/day the unit cost would be ap- Production/hour 38m3 (53 pcs) proximately $ 14.30/m3. By increasing working time to nine hours the cost would reduce to about 13.35/m3. )position includes untangling strops and lowering rigging in the bush. DISCUSSION SD = Standard Deviation

Outhaul and inhaul times have been The Madill 122 was capable of high standardised to 200m by the equa- production in the relatively small piece size tions: of .71m3. While cycle times were not as fast as they could have been (due to tail- Out = .315 + .0016 (dist), 2 = .49 rope wrapping problems) they were regular Inh = .428 + .0025 (dist), 1 = .50 and the average drag size of 4m3 was enough to return good hourly production. Lineshift times averaging less than 5 Considering the relatively small .71m3 minutes were possible with the mobile piece size, average drag size was realistic tailhold. Generally delay times were low at with 5.8 pieces being hooked onto four less than one minute per cycle. As a conse- strops each cycle. The largest drag was 11 quence, utilisation of 82% was recorded. pieces. Hook on was actually quicker with Lower utilisation would be expected over a three breaking-out, but fewer logs were at- longer term. -6-

Table 2 :Indicative costings for Madill 122

Cost Centre 8 hr day 9 hr day

Hauler 1410 1440 Loader 525 555 Labour (10 men) 1530 1650 Operating supplies 230 230 Overheads 75 75 Prof it (10%) 3 70 390

Total 4150 4345

The cost per m3 can be significantly PETERSON, J.T. (1987) : "Harvesting reduced by working an extra hour per day. Economics: Grapple Yarding Second- This crew worked a nine hour shift and that Growth Timber". FERIC Technical reduced the unit cost by seven percent. Ex- Report TR-75. tended hours per shift or double shifting will be necessary for high cost machines PETERSON, J.T. (1988) : "Harvesting like the 122 to be viable in New Zealand. Economics: Two Case Studies of a Cypress Loggers will need to use the most efficient 7280 Swing Yarder FERIC Technical Note systems possible to offset the high costs of TN-115. swing yarders and this may include adding extra capital to mechanise some parts of PREBBLE, R.L. (1988) : "A Study of Log the operation. Length and Tree Length Extraction using a Washington 88 Hauler". LIRA' Project The 122 has basically been designed for Report P.R. 34. grapple yarding and as such it has limited line capacity with 22mm ropes (less than PREBBLE, R.L. (1989) : "A Study of 900m on the tailrope drum). S. Madill Ltd Landing Activities in PNW Swin Yarder now manufacture a 123 model which has Operations". LIRA Brief Report (!n prep.) 715m of mainrope and slackpuller capacity and 1350m of tailrope capacity. This new WELLS, G.L. (1981) : "Costing Handbook machine is more expensive at US$595,000 for Logging Contractors". LIRA Hand- but it will be better suited to MSP opera- book. tion with the capacity to work over longer distances.

The costs stated in this Report have been derived using the procedure shown in the REFERENCES LIRA Costing Handbook for Logging Con- tractors. They are only an estimate and do MACDONALD, J. (1987) : "Productivity not necessarily represent the actual costs for and Profitability of the Madill 122 when this operation. Grapple Yarding B.C. Coastal Second- Growth Timber". FERIC Special Report NO. SR-48. N.Z. LOGGING INDUSTRY RESEARCH ASSOC. INC. PEASE, D.A. (1988) : "Delimbers join P.O. Box 147, Yarders in Mountainous Terrain". Reprint ROTORUA, NEW ZEALAND. from Forest Industries, 1988.